Bruxism is thought to involve parafunction, abnormal oral habit or parasomnia. Bruxism can have a serious effect on health, as it causes such conditions as dental attrition and tooth fracture, pain and discomfort in masticatory muscle, and temporomandibular disorders.
Although occlusion was previously thought to be involved in the onset of bruxism, it has recently become clear that occlusion is hardly involved at all in the onset of this condition (for example, see the non-patent reference 1).
To date, treatment for bruxism has only involved such splint (Nightguard) therapy as insertion of a splint similar to a boxing mouthpiece that prevents the upper and lower teeth from touching, cognitive behavioral therapy to train the individual to consciously prevent the involuntary movements, biofeedback therapies, and pharmacotherapies. Of these, the splint therapy is extremely expensive and questionable in terms of its effectiveness. With pharmacotherapies, there have been reports that an anxiolytic agent such as diazepam, a tricylic antidepressant, a muscle relaxant, and L-dopa are effective as a preventive or therapeutic agent for bruxism (for example, see non-patent reference 2). However, none of these methods provide a fundamental therapy for bruxism. Therefore, there is a strong need for an effective and fundamental therapy for bruxism.
[Non-Patent Reference 1]
    Lavigne G. J, Manzini C. Bruxism. In: Kryger M H, Roth T. and Dement W, eds. Principles and practice of sleep medicine. Philadelphia: W B Saunders, 2000: 773-85.[Non-Patent Reference 2]    Lobbezoo F, Lavigne G J, Tanguay R, and Montplaisir J Y. Mov Disord 12: 73-78, 1997.